


Secret ~Black Vow~

by snowdroppanda



Category: Kuroshitsuji | Black Butler
Genre: Alternate Universe, Based on a Vocaloid Song, Don't have to squint for Sebaciel with this one, F/M, M/M, One Shot, Sad, Songfic
Language: English
Status: Completed
Published: 2014-09-23
Updated: 2014-09-23
Packaged: 2018-02-18 11:54:42
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,691
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/2347574
Author URL: https://archiveofourown.org/users/snowdroppanda/pseuds/snowdroppanda
Summary: <blockquote class="userstuff">
              <p>Based on the Vocaloid song, "Hitmitsu ~Kuro no Chikai" (Secret ~Black Vow~), Ciel is an angel that does whatever it takes to be with Sebastian, a human.</p>
            </blockquote>





	Secret ~Black Vow~

**Author's Note:**

> Second ever Kurofic, woo. I did gender-bending with the song, and (as stated in my profile) I brought in my "twin theory" OC, Isabelle. I don't own Kuro or the song, though Isabelle is my brainchild~.

_An injured angel, who had lost his way..._

 

Ciel sat alone on the sidewalk, eyes closed and head tilted back. He didn't want to remember what had just happened to him; his breathing was still laboured from the heartbreak. His life should have been perfect - he was an angel in Heaven, and had even captivated the heart of another angel. Their love was pure and untainted. Passionate, but not lustful, as that was considered a sin. They blended into each other effortlessly, and provided the love and comfort each other needed. However, as the years passed, it wasn't enough for Ciel. The insatiable angel desired more than what his lover could provide. It grew to the point that the dark blue-grey haired angel broke off their relationship and tumbled down into the mortal world that he'd silently watched for too long.

The young male fell to his knees on the streets, not caring that any humans who happened to be wandering about in the early evening would see the large, almost blindingly white wings on his back. Tears streamed down his cheeks in longing and frustration. Had he really been so moronic to give up the closest thing he had to paradise? It was obvious Elizabeth loved him with all her heart and soul, and Ciel loved her back, choosing to ignore the small darkness in his heart that was never truly satisfied. Though his feelings were genuine for her, he couldn't give his all to her, something that the virtuous female deserved. The blonde was utterly angelic, even amongst the rest of the divine, and she needed someone who could devote everything they had to her. As much as he wanted to be that person... he couldn't.

It was with those thoughts that Ciel willingly let himself fall from the clouds, and instead sorrowed in the fading sunlight.

Until the light was cut off by a tall figure.

 

_...the instant when their eyes met..._

 

Ciel first saw the extended hand, covered by a white glove. Not stopping there, the bluenette's eyes trailed upwards over the very masculine - and very handsome - figure until it landed on the masculine facial features. At once, the young angel's heart stopped. Everything about this stranger drew him in, and he found himself frozen. Though the man was dressed in dark clothes, aside from his gloves, the ring of dim sunlight behind him made the stranger glow as though he was Heaven sent. Ciel couldn't help but notice how the light shone on the black silk strands of hair that framed his face. His fine, sculpted cheekbones, firm jawline, soft lips that were upturned in a gentle smile...and those crimson eyes that made Ciel feel like he could be lost in them forever.

It didn't register in the angel's thoughts that his wings were completely exposed to this man, revealing that, although he was wearing a relatively normal white suit, he was very obviously not human. By the tender and not shocked expression on the stranger's face, Ciel vaguely assumed the man didn't care about that fact either. The emotions that were swelling up in his chest were reminiscent of those that he felt with Elizabeth, only stronger. And as he reached up to take hold of the man's offered hand, Ciel could swear that even the unsatisfied darkness in his heart was singing in pleasure.

 

_...to grant an unforgivable love between a human and an angel..._

 

From that day, Ciel was obsessed with the man that he learned was named Sebastian. The man became his everything, and Ciel desired nothing more than to be everything for him. All the feelings that he'd longed for during his long life was right in front of him. The passion and love that he felt with Elizabeth was increased ten fold when he even looked at Sebastian, more so during the times they were able to touch and kiss. The raven haired man completed him in all the ways he never thought possible. That darkness in his heart was soothed and comforted until it succumbed to the growing fire in the angel. _This_ was the paradise he longed for. There was nothing more he could've asked for.

Yet...Sebastian was still human.

And engaged.

The days dragged on, and their secret time spent together became less and less frequent. On the other side, Ciel found himself resorting to watching Sebastian more and more as the other man planned his marriage to some woman. Although Ciel was certain of Sebastian's love for him, there were too many complications for them to be in a relationship. Sebastian's engagement. The two being males. Ciel being an angel and Sebastian being human. There was no possible way for the two to ever be together, and they both begun to understand that. Whenever Sebastian smiled at Ciel, it always had a melancholy to it, one that the bluenette couldn't stand. Though they knew they made each other happy, it was also obvious that they made each other miserable as well with their forbidden affair.

Ciel knew what he needed to do.

 

_...the only way was to demolish everything._

 

By sacrificing all but one feather of their wings to the devil, angels became 'fallen' and could be reborn - in a sense - into the mortal world. They would retain what they wanted, and change what they didn't want. But, having been labeled as 'fallen', they would be forever unable to reenter the gates of Heaven, sentenced instead to live as a demon until they were completely claimed by Hell. It was not a choice a normal angel would make.

 

_With my spotless heart thrown away, as long as I can live in our love,_

_let me relinquish my wings and offer my body to the devil._

 

Then again, Ciel was never a normal angel.

 

_The groom, dressed completely in darkness..._

 

Sebastian had been sorrowful ever since the day he laid eyes on the angel. Though he never believed in love at first sight, it had been exactly that. The pearly white wings neither surprised nor frightened him. Why would they, when they so obviously belonged to a being such as that? Ciel's stunning, ocean blue eyes captivated and enraptured the man. His dark blue-grey hair, his slim body... Sebastian considered himself to be bisexual, though women drew his attention more than males, but after seeing Ciel, he begun doubting himself. It wasn't long before the two begun their forbidden affair, and shortly after, Sebastian couldn't summon up his desire for Mey-Rin as he had when they got engaged.

As much as he loved Ciel, he knew they couldn't be together. However, he didn't expect his despair to significantly increase the day before his marriage. Expecting Ciel to be at his house for comfort was ridiculous, the man knew. What surprised him was the single white feather that he found on the floor. The feather could've only belonged to one person, and for the first time in several years, Sebastian felt his normal composure fall apart for miserable tears at the realisation.

Ciel was gone.

 

_...the instant when their eyes met..._

 

Sebastian first saw the extended hand, covered by a black glove. Not stopping there, the raven haired man's eyes trailed upwards over the very feminine - and very beautiful - figure until it landed on the feminine facial features. At once, the groom's heart stopped. Everything about this stranger drew him in, and he found himself frozen. The woman was dressed in dark clothes, and standing in the shade of a large tree, she radiated a dark beauty that was both dangerous and entrancing, almost like a dark angel, exiled from Heaven. Sebastian couldn't help but notice how the light shone on the dark blue-grey silk strands of hair that framed her face and cascaded halfway down her back. Her soft, adorable cheekbones, firm jawline, light pink lips that were upturned in a gentle smile...and those ocean blue eyes that made Sebastian feel like he could be lost in them forever.

It didn't register in the man's thoughts that his fiancée was frantically calling to him from the archway, nor did he notice how he was beginning to walk towards the strange female as though in a trance. By the tender and not shocked expression on the stranger's face, Sebastian vaguely assumed the woman didn't care about that fact either; maybe even expected it. The emotions that were swelling up in his chest were reminiscent of those that he once felt with Ciel, and staring into the female's blue gaze, Sebastian could only wonder if - just maybe - she was Ciel. And as he reached to take hold of the woman's offered hand, Sebastian could swear that the part of him that died upon seeing the feather only the previous day had revived and was singing in pleasure.

 

_...even this chaste vow that I'd been holding has become tarnished..._

 

That night, Sebastian and Isabelle didn't hesitate in giving themselves to each other. They had been nothing but strangers that afternoon, but the spark that flared between them was too powerful to ignore. To Sebastian, it was anything but odd. Though Isabelle had a lithe, feminine body, the man couldn't help but feel as though he'd touched it before. In a way, it felt to him that Isabelle was familiar with his body and lips as well. All the ways she touched him was the same as when he'd secretly make out with Ciel. The angel's lips had been the only ones to mold with his in a perfect way - and now it was the same with Isabelle. Only Ciel's body pressed against him in just the right way, but now this woman did as well. And when they passionately had sex, Sebastian's erect organ fit perfectly inside Isabelle's warm and welcoming body.

For both of them, this was paradise.

 

_I, captivated by you, will only become more sordid..._

 

The next morning, Sebastian wasted no time in proposing to Isabelle. He'd already given up his previous engagement when he left with the bluenette, and there were no other complications in their future relationship. Though his heart had been stolen by the angel, somehow Sebastian sensed that this woman actually held it. And although it should've been a concern, he couldn't help but feel that it was just the way it should be.

 

_...to the point where I will bemoan even my regrets._

 

Isabelle recalled everything that happened since she fell to the mortal world as an angel and met Sebastian. Her death and rebirth didn't change that. It was unfortunate that she had to resort to such tactics, but the saying about doing crazy things while in love held true. She was with the person she loved above all, and there was no possible way she could regret what she did, or accepting his proposal.

 

_Ah, the unforgivable sin_

_turns into an incurable wound and continues on..._

 

Sebastian sat upon the lawn in the back of his house, waiting for Isabelle to return. He was filled with such joy and happiness that he never thought possible. Finally, he was with his romantic soulmate. It had been just that morning that they became engaged, and only yesterday that they met and connected in the most intimate of ways. He knew there were people that would say they were moving too fast, but that didn't matter to him. Nothing mattered as long as they were together. There were no words to express how much he loved and cared for Isabelle, nor how she completed him. He was sure they'd be together for eternity.

 

_...then a furious arrow of judgment_

_pierces right through the man covered in darkness._

 

So lost in thought, Sebastian didn't notice the angel landing behind him with a murderous gaze in her eyes. Rumours about the fallen angel Ciel had spread throughout Heaven, and when they reached the ears of Elizabeth, she could hardly repress her disgust. _Her_ Ciel had given up his wings and become a human female for the unsuspecting man sitting feet away from her. It was a mortal sin that was unheard of until now. The blonde angel was one praised for her forgiveness and bubbly demeanor, but the pain and fury that now coursed through her veins was too much to be ignored. This human and her former angelic lover were to blame, and both deserved to be punished - not only for what they did to her, but the offense they committed upon God.

Sebastian turned around just in time to see the angel shoot the bullet straight at his chest.

Isabelle walked up in time to see a flurry of white wings disappear, revealing her deceased lover on the ground; his blood still flowed out, staining the flowers a gory red. The bluenette rushed over to kneel down next to him, unable to speak or cry out in despair. Carefully, she lifted his body and cradled his limp head to her chest as tears ran freely down her cheeks. He was dead. He was dead, and it was all her fault. All she'd wanted was to live and love freely with this man, and because of that, he paid the ultimate price. Her head tilted back, dejected blue eyes staring at the cloudy sky. Though she didn't see the face of the killer, she could almost guess it was Elizabeth. The angelic goddess was as saintly as she could be, but held an unrivaled fury, especially when it came to crimes of sacrilege. There would be no pleading to God to spare Sebastian.

The tears ceased as Isabelle's azure gaze turned back down to her lover. Even though she wouldn't be able to plead to the Heavens to revive Sebastian, there was still one option left to restore his life. One hand came up, gently lifting his chin so that she could tenderly kiss his cold lips. Her selfishness had brought this upon him, and now, she was going to repair this mess. It was no longer her happiness she was concerned about; it was his.

"My dear, lying cold.. I will spend all my life for you as I swore on that day. My sin against God... All my acts of treachery should be paid with my death... so, I will die for you... I believe.. that is my fate."

Sebastian's crimson eyes slowly opened, and when they focused, they settled on Ciel, dressed in the same clothes that Isabelle had been wearing. It only took a moment for him to realise that they had been one in the same, and only a moment longer for him to comprehend what happened. He remembered the angel that'd shot him, and remembered the darkness of death. Ciel was also an angel - obviously his love had revived him. He should have been delighted, but there was something unsettling about the heartbroken smile that Ciel wore. Before Sebastian could even ask, Ciel's body disappeared, leaving behind a single, black feather.

In an instant, Sebastian knew what truly happened, and clutched the feather. Unlike the last time he found the white feather, tears spilled out of his eyes without pause. There had been a finality in the look they exchanged, and the raven haired man knew that he wouldn't see his lover again in that life. He clenched the feather tightly to his chest, torn from all sense of reality, as he continued sobbing. His paradise and happiness was lost before he had a chance to fully experience it. Amid the sobs, Sebastian cursed the heavenly beings that caused his suffering, and swore that he would do whatever it took to be with Ciel again, even in death. His angelic lover sacrificed everything to be with him...and he would do the same.

 

_A fallen angel who had lost his wings,_

_and a groom tainted completely in the darkness,_

_even if they were to plunge to the bottom of the abyss,_

_they will continue to hold to the tie of their vows,_

_and continue on embracing their unforgivable sin._

 

_When the fruit of sin becomes completely rotten,_

_they will meet each other again. Until then..._

**Author's Note:**

> The lyrics are pretty much in Ciel's pov, so any personal pronouns (I, me) refer to Ciel/Isabelle.  
> For those interested, the full lyrics are here: [Himitsu ~Kuro no Chikai~](http://www.animelyrics.com/doujin/vocaloid/himitsukuronochikai.htm)


End file.
